Cosmology and dark energy with future HI galaxy surveys - Kanagawa Uyamauchi/seminar/... · 2019....
Transcript of Cosmology and dark energy with future HI galaxy surveys - Kanagawa Uyamauchi/seminar/... · 2019....
Cosmology and Dark Energy with future HI galaxy surveys
Daisuke YamauchiKanagawa University
2019/02/19 Cosmological challenges to dark matter, dark energy, and galaxy formation @Sao Paulo, Brazil
Cosmological observables
◆Baryon Acoustic Oscillation
◆Redshift-Space Distortion
◆Gravitational Lensing
CMB temperature map
Line-of-
sight
Redshift-Space Distortion
[SDSS-III BOSS]
Lin
e-o
f-si
ght
[Mp
c/h
]
Angular direction [Mpc/h]
→ radio
→ optical
➢Cosmic Microwave Background
➢Large-Scale Structure
+ Radio (New!)
complementary
Why “radio” frequency?
p e p e
◆Hyperfine transition radiation of neutral hydrogen:21cm line
wavelength λ = 21 cm ( ν=1.4GHz : radio freq )
1S
Hyperfine structure
5.9×10-6eV
Takahashi and de Souza’s talk (yesterday)
21cm lineobservations
Why “radio” frequency?
= Information of growth!
Spatial distribution of IGM/galaxies in
dark age/structure formation
HI mainly lives in IGM.
Dark Age
HI mainly lives in galaxies.
Formation epoch
Brief Review of
Square Kilometre Array
➢ Open a new window for Astronomy
SQUARE KILOMETRE ARRAY
MID (ν=0.35-10GHz) LOW (ν=0.05-0.35GHz)
collecting area : 1km2
50MHz -- 104MHz
available full-sky
✓ New frequency regime
✓ High sensitivity
✓ Wide sky coverage
✓ High angular resolution
Phase 1: 200 dishes across 150km
of Southern Africa
Phase 1: 130,000 antennas
(512stations*256antennas) across 80km of Australia
SKA Phase 1(2019 – 2028)
Phase 2: 1,000,000 antennas across
200km of Australia(2028 – )
Phase 2: 2,500 dishes across
3500km of Southern Africa(2028 – )
Movies from presentation by R. Brown (Science Director, SKAO)
Construction will start soon!
?
Scientific goals of SKA
◆ Fundamental physics : Gravity, Dark Energy, Cosmic Magnetism
◆ Astrophysics : Cosmic Dawn, First galaxies, galaxy assembly and evolution, +…
◆ The unknowns : transients + ...
Cosmic Dawn Magnetism GravityGalaxy &
Transients
Dark Energy
The SKA aims to solve some of the biggest questions.
SKA Science Book/Red Book
135 Chapters, 1200 Contributors, 2000 Pages!
https://www.skatelescope.org/books/
◆Red Book[Bacon+DY+(2018)]
◆ SKA Science Book [2015]
Contributions from Japanese community
http://ska-jp.org/ws2015/SKA-JP/talks/SKAJP_Science_Book_2015.pdf
➢ SKA-Japan Consortium
◆Review (in English) [DY+(2016)]
◆ SKA-Japan SKA Science Book [2015, in Japanese(sorry!)]
Brief review of
SKA Cosmological Surveys
➢ Radio continuum survey• Measures galaxy synchrotron radiation radio emissions, which is
advantageous in detecting high-z galaxies.
• Provides a featureless spectrum → The redshift info is not available.
✓ HI galaxy redshift survey
✓ Mid-freq HI intensity mapping [after CD/EoR]
➢ HI [21-cm] line survey
• The 3D matter distributions can be reconstructed.
• The detection of individual galaxies is not required.
• The integrated HI intensity of several galaxies in one pixel is measured.
✓ Low-freq HI intensity mapping [before CD/EoR]
• Measure the large-scale distributions of the HI inside the IGM via the brightness temperature.
◆ The redshifting of HI-line provides the redshift information.
Takahashi’s talk (yesterday)
de Souza’s talk (yesterday)
Observable SurveySKA
Phaseredshift
Sky coverage
Galaxy number
HI [21cm line]
HI galaxy survey
(gal)
Phase-1 z<0.8 1/8 ~ 107
Phase-2 z<2 3/4 ~ 109
HI [21cm line]
HI intensity mapping survey
(MID-IM)
Phase-1 z<3 3/4 --
Phase-2 z<3.7 3/4 --
HI [21cm line]
HI intensity mapping survey
(LOW-IM)
Phase-1 3<z<27 1/40 --
Phase-2 3<z<27 3/4 --
Synchrotron radiation
Continuum survey (conti)
Phase-1 z<6 3/4 ~ 108
Phase-2 z<6 3/4 ~ 109
Optical e.g. Euclid z<2 3/8 ~ 108
S = 70(SKA1gal), 5(SKA2gal), 1(SKA1cont), 0.1(SKA2cont) [μJy] Δθ = 1(SKA1), 0.1(SKA2) [arcsec], tint = 104 [hr]
Observable SurveySKA
Phaseredshift
Sky coverage
Galaxy number
HI [21cm line]
HI galaxy survey
(gal)
Phase-1 z<0.8 1/8 ~ 107
Phase-2 z<2 3/4 ~ 109
HI [21cm line]
HI intensity mapping survey
(MID-IM)
Phase-1 z<3 3/4 --
Phase-2 z<3.7 3/4 --
HI [21cm line]
HI intensity mapping survey
(LOW-IM)
Phase-1 3<z<27 1/40 --
Phase-2 3<z<27 3/4 --
Synchrotron radiation
Continuum survey (conti)
Phase-1 z<6 3/4 ~ 108
Phase-2 z<6 3/4 ~ 109
Optical e.g. Euclid z<2 3/8 ~ 108
S = 70(SKA1gal), 5(SKA2gal), 1(SKA1cont), 0.1(SKA2cont) [μJy] Δθ = 1(SKA1), 0.1(SKA2) [arcsec], tint = 104 [hr]
Even phase-1 IM and RC surveys will cover the extremely large survey volume
(available full sky out to very high-z)!
Observable SurveySKA
Phaseredshift
Sky coverage
Galaxy number
HI [21cm line]
HI galaxy survey
(gal)
Phase-1 z<0.8 1/8 ~ 107
Phase-2 z<2 3/4 ~ 109
HI [21cm line]
HI intensity mapping survey
(MID-IM)
Phase-1 z<3 3/4 --
Phase-2 z<3.7 3/4 --
HI [21cm line]
HI intensity mapping survey
(LOW-IM)
Phase-1 3<z<27 1/40 --
Phase-2 3<z<27 3/4 --
Synchrotron radiation
Continuum survey (conti)
Phase-1 z<6 3/4 ~ 108
Phase-2 z<6 3/4 ~ 109
Optical e.g. Euclid z<2 3/8 ~ 108
S = 70(SKA1gal), 5(SKA2gal), 1(SKA1cont), 0.1(SKA2cont) [μJy] Δθ = 1(SKA1), 0.1(SKA2) [arcsec], tint = 104 [hr]
When the Phase-2 is constructed, the flux threshold will be drastically improved (~5μJy), providing the spectropic
survey of 1 billion (!) HI galaxies can be delivered.
A Key Science with SKA
➢List of highest priority SKA1 science
“Constraints on primordial non-Gaussianity and tests of gravity on super-horizon scales”
[SKA Phase 1 Science Priority Outcomes]
Cosmology and Dark Energy with HI galaxy surveys
How do we characterize Dark Energy?
◆Expansion history
◆Growth of large-scale structure : δ=δρ/ρ
Equation-of-state
Growth index
Dark Energy Equation-of-State [Planck XIV(2013)]
Cosmological Constant
Yamaguchi’s talk
Dark Energy Equation-of-State[Planck XIV(2013), SKA Science Book(BAO) (2015), Bull (2016)]
SKA2(gal) BOSS[current]
SKA1(MID-IM[B1])SKA1(MID-IM[B2])
The SKA1 MID-IM survey will be able to provide comparable constraints with e.g. Euclid, and the SKA2 HI galaxy survey is expected to allow further improvements.
Growth index and Dark Energy
GR
f(R) gravity
Massive gravity
DGP braneworld
[Bull(2016), SKA Science Book(RSD) (2015)]
Gro
wth
ind
ex
Equation-of-state
KGB gravity
◆ can trace the (linear) growth history.◆ can distinguish and hopefully exclude the dark energy models.
SKA2 (gal)
SKA1(LOW-IM)
SKA1(MID-IM[B1])
BOSS
SKA1(MID-IM[B2])
[Bull(2016), SKA Science Book(RSD) (2015)]
Gro
wth
ind
ex
Equation-of-state
◆ can trace the (linear) growth history.◆ can distinguish and hopefully exclude the dark energy models.
Growth index and Dark Energy
Quasi-nonlinear Growth and Dark Energy
[DY+Yokoyama+Tashiro (2017)]
2nd order index
◆ Even if wDE=-1 and γ=γGR, it is NOT necessary that our Universe is described by ΛCDM with GR.
◆ Non-Gaussianity should be generated from nonlinear growth.
can carry new info that is not included in the linear-order!
nKGB
Horndeski(wDE=-1, γ=γGR)
Growth index
2n
do
rde
r in
dex
SKA2 (gal)
SKA1(gal)
Euclid
Dark Energy and Scalar-Tensor Theories
Scalar-Tensor Theories have been widely studied as an alternative to the dark energy.
GW170817+GRB 170817A gave the stringent constraint on the speed of GW : |cGW/cEM-1|<10-15, which rules out theories which predict a variable GW speed.
The most general framework that has been developed so far
Yamaguchi’s talk
[Langlois+Saito+DY+Noui (2018)]
[Hirano+Kobayashi+DY+Yokoyama (2019)]
Growth index and Scalar-Tensor Theories◆ The precise measurement of growth of structure can provide
the severe constraint on the wide class of modified gravity.
αH/(
1-Ω
m)
β1/(1-Ωm)“DHOST” parameter
“GLP
V”
par
amet
er
[Gray(stellar structure): Kobayashi+DY+(2015), Saito+DY+(2015), Sakstein+(2015) ]
We hunt down modified gravity by combining this with local constraint!
[Hirano+Kobayashi+DY+Yokoyama (2019)]
Growth index and Scalar-Tensor Theories◆ The precise measurement of growth of structure can provide
the severe constraint on the wide class of modified gravity.
[Gray(stellar structure): Kobayashi+DY+(2015), Saito+DY+(2015), Sakstein+(2015) ]
BOSS:|γ-6/11|<0.1
SKA :|γ-6/11|<0.007
αH/(
1-Ω
m)
β1/(1-Ωm)“DHOST” parameter
“GLP
V”
par
amet
er
We hunt down modified gravity by combining this with local constraint!
RSD and coupling between DE and DM
[Kimura+Suyama+Yamaguchi+DY+Yokoyama(2017)]
In the presence of a coupling between DE and DMthrough the conformal-disformal metric:
e.g.) A=1,B=α/X
The information of coupling is encoded in the peculiar velocity field = Redshift-Space Distortion!
Chibana’s talk (tomorrow)
➢ The SKA will provide new information of DE andhopefully single out the true model of DE.
➢ Other topics :Various Synergies
Thank you!
Summary
With CMB observations:Delensing[Namikawa+DY+Sherwin+Nagata (2015)]
With particle physics:Lepton asymmetry, ν,…
With optical galaxy survey:Multitracer
[Kohri+Oyama+Sekiguchi+T.Takahashi (2014),…]
[DY+ (2014), DY+K.Takahashi(2015), DY+Yokoyama+K.Takahashi(2016)]